Electric circuit breaker



Nov. 4, 1947. B. M. H. P. FERMER` ELECTRIC CIRCUIT BHEAKER Filed 0ct. 24, 1942 Patented Nov. 4, 1947 ELECTRIC' CIRCUIT BREAKER Bernard Marie Hilaire Paul Fernier, Lyon, France, vested in the Attorney General of the United States Application ctober 24, 1942, SerialiNo. 463,172 In France June 18, 1941 2y Claims.

This invention relates to circuit breakers and has for its principal object to provi-de a breaker with improved means for extinguishing any arc which may be formed on separation of the contacts.

In the particular embodiments oi my invention herein disclosed I provide a circuit breaker having iixed and movable contacts, associated with each of which is a means for creating a blast of air, directed toward the arc, on separation of the electrodes.

The arc extinguishing means associated with the stationary contact preferably consists of an insulating tube surrounding the such contact and partly surrounding the movable contact in circuit closing position.

The tube serves to direct a blast of air or gas against the arc as the movable electrode leaves the insulating tube in its circuit breaking movement, this blast being created either by the air inr the tube, which has been heated by the arc, or preferably by the arc acting on the walls of the tube.

The arc extinguishing means of the movable electrode comprises a nozzle for directing an eX- tinguishing current of air or gas which has been compressed by movement of the electrode or associated movable part.

Other objects and advantages of my invention will appear from the following description taken in connection with the accompanying drawing wherein- Fig. 1 is a central longitudinal sectional view, partly in elevation, showing one embodiment of my invention.

Fig. 2.is a similar View but showing a modification and wherein lighter movable parts are employed. 1

Fig. 3 is a detail section View showing means for retarding the timing of the extinguishing blast of compressed air,

Fig. 4 is a detail View showing a modification of a part of the structure shown in Fig. 3.

Fig. 5 is a detail view showing a modied form of blowing nozzle.

Fig. 6 is a longitudinal sectional View and Fig. 7 a side elevation showing an arrangement of eX- pansion chamber for heated self-generated gases which form the extinguishing means; these latter figures showing a disconnecting switch in parallel to the circuit breaker.

Fig. 8 is a sectional view in an enlarged scale of a detail of the structure shown in Fig. l, illustrating a part not shown in Fig. 1.

In Fig. 1 reference character l represents a iixed electrode and 2 an insulating tube forming a chamber surrounding the movablev electrode 3 when in circuit closing position. The movable electrode 3 is formed at its rear end with a pin adapted to engage in a slot formed in the end of an operating arm B pivoted tothe frame of the circuit breaker, Current is transmitted' to the contact 3 by spring contact fingers 5 carried by a stationary casing 6'.

A piston B is fixed on the electrode 3 by means of a sleeve 'I secured to the movable electrode-by a spider 1 which permit air, in the cylindrical casing 6', compressed by the piston 6 to enter the tube or sleeve 1 and thence pass into the tubular extension 8 of the casing 6 which is co-axialy with the movable contact and in whichthe sleeve I slides.

Tubular extension 8 forms a blowing chamber and has an opening 9 forming a blowing nozzle. Apertures Il] may be made inthe cylinder 6 to prevent compression or rarication infront of the piston and suitable means, such as a relief or one-Way valve 22 cooperating with openings 23 and 24 through the piston interconnecting both sides of the latter (see Fig. 8), will beA employed for admitting air behind the piston 6 as the electrode 3 is moved to closed position and conning this air as the electrode is moved in the opposite direction to permit the air to be compressed for ejection from the nozzle 9.

In order to delay the action of the compression and to shorten the compression stroke of the piston, apertures H are provided in the cylinder 6 in a position necessary to produce the desired effect.

The breaking of high intensity currents occurs when the electrode rod 3 is withdrawn from the extremity of the insulating tube 3 and the cutting off of low intensity and mean currents takes place on the first passage of the current through zero after the free end of the movable contact has passed the neck of the blow nozzle 9. The construction and arrangement is such that the end of the movable contact, in the open circuit position will be in that part of the neck ofy the nozzle El Where it is subject to the strongest blast.

The quantity of the air wasted before saidmovable Contact reaches the circuit breaking-position is reduced to a minimum because of the slight clearance between the electrode 3 and the rim of the port in nozzle 9. In order to avoid' the loss of air, the compression may be caused to take place only after said contact has completed a certain part of its stroke, for instance, by a suit-- able location of the mentioned openings II in the cylinder 6.

Referring to Fig. 2, the fixed electrode I is also surrounded by the insulating tube 2. The movable electrode passes through a blowing chamber tube 8 provided with the blowing opening or nozzle 9. Tube 8 and electrodes 3 as will be seen, are shorter than the corresponding parts in Fig. 1. The operating mechanism, includes a pivoted lever 4 which operates the piston of a compressor 6 which in turn supplies to chamber 8 the arc extinguishing fluid through a conduit I2 in the insulating support.

The circuit breaker of Fig. 2 is employed where economy of space is desired.

In order to shorten the compressing movement of the piston, apertures II are provided so that the compression movement will not begin until the piston has covered the aperture.

In another modiiication, shown in Fig. 3, the operating-lever may be provided with a pin I3 engaging a slot Id provided in the rod of piston 6', the pin I3 being yieldingly connected by a spring I5 to a fixed block I6 of said piston rod. At the beginning of the contact disengaging motion, the lever Ii compresses the spring I5 without appreciably moving the piston 6 which is sub-- jected to the increase of pressure in the fluid in the cylinder. This lost motion between the lever 4' and the piston 6 allows the movement of lever 4 and contact 3' to be quickly accelerated to full speed.

The same result may be obtained by using, in place of a straight lever 4 linked to the push-rod of the piston, a bell-crank lever 25 represented in Fig. 4. The extremity A of said bell cranklever is connected to the movable electrode, whereas the extremity B of said crank-lever is connected to the piston rod. The angle between the two arms of the crank-lever, their lengths and their arrangement are such that during the initial separating movement of the electrodes, i. e., when the extremity A starts to move downwards as shown for example in Fig. 4, the extremity B and the piston connected thereto by means of the paths c-d, c-d, in Figs. l and 2. In order to improve the protection of said leakage paths, the nozzle may be provided, as shown in Fig. 5, with a fin, protecting the leakage paths c-d-e, c-d-e from the particles blown from the aperture of the insulating tube 2.

Figs. 6 and '7 show the construction of an expansion chamber for a. high power switch, having a pair of circuit breaking contacts 3,3', the crosssection of which is too small to stand. continually the normal current. Therefore, said contacts are shunted by a disconnecting switch comprising electrodes E0, 20 parallel to that of the circuit breaker.

The enclosure I8, in which the gases expand before being expelled includes a U-shaped channel I9 through which the disconnecting electrode 2! passes, while the cutting-oir electrode 3 passes through the insulating tube ZI, the latter being surrounded by the chamber I3. The cutting-oliF of the disconnecting electrode precedes that of the circuit breaking electrode Whereas its engagement follows that of the cutting-off electrode.

The special shape of the channel provides good ventilation for the electrode 20 and at the same time the particular shape of the chamber resulting from the presence of the channel contributes to a better guiding for the evacuation of the arc extinguishing gases.

It will be understood that instead of providing only one channel in the chamber, several of such channels may be used through which several disconnecting electrodes arranged in parallel with respect to the circuit breaking electrode, will pass.

Apart from the advantages, already mentioned, the electric circuit breakers embodying the present invention possess numerous additional advantages over similar apparatus heretofore known. The very slight clearance between the electrode-rod and the nozzle enables the pneumatic blowing of the arc to be effected only at the most advantageous moment and in a definite geometrical position, irrespective of the current intensity, when the extremity of the electrode arrives above the neck of the nozzle, as distinguished from circuit breakers using a gas-operated valve the operation of which is unreliable and uncertain.

rlhe nxity of the blowing means, nozzle and airconduct reduces the weight, thence the inertia of the movable parts particularly in the embodiment of the invention shown in Fig. 2 and causes the engagement and disengagement of the contacts to be effected with greater speed.

For equal normal current intensity, the diameter of the blowing electrode-tube in electric circuit breakers heretofore used in greater than the diameter of a contact rod according to the present invention, and therefore the acceleration imparted to the movable part bythe pressure of the arc-gases or of the air compressed by the arc-heat in the chamber adjacent to the fixed electrode above the insulating tube closely surrounding the movable electrode in its engaged position, will be greater, and the kinetic energy, that is to be damped, will also be greater than in electric circuit breakers embodying the present invention.

I am aware that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiments of the invention to be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

l. An electric circuit breaker, in combination a iixed electrode, a movable electrode opposite to and cooperating with said fixed electrode to make and break the contact, an insulating tube having one open end and surrounding said xed electrode, said movable electrode constituting a solid rod and being constructed and arranged to enter said tube at its open end in order to engage said fixed electrode in the closed position of the circuit breaker, a compressor for generating a gas blast to extinguish the arc drawn between the electrodes, said compressor comprising a stationary cylinder a piston cooperating with said cylinder, operating means to move said movable electrode in and out of engagement with said xed electrode, a blowing chamber surrounding said rod, said blowing chamber forming an extension of said cylinder, said rod being straight and passed through said cylinder and said chamber, a sleeve open at both ends surrounding said rod in said cylinder with space left between said rod and the inner Wall of said sleeve, spiders connecting said sleeve to said rod, a connection from said sleeve to said piston whereby the gas compressed by said piston upon separation of the electrodes is forced through said sleeve to said blowing chamber, a nozzle in said chamber opposite said insulating tube to discharge the gas blast, said rod being passed through said nozzle with little clearance in the closed circuit breaker position and being adapted to uncover the nozzle opening during the separation of the electrodes.

2. An electric circuit breaker, in combination a fixed electrode, a movable electrode opposite to and cooperating with said fixed electrode t0 make and break the contact, an insulating tube having one open end and surrounding said xed electrode, said movable electrode constituting a solid rod and being constructed and arranged to enter said tube at its open end in order to engage said fixed electrode in the closed position of the circuit breaker, operating means to move said movable electrode in and out of engagement with said fixed electrode, a stationary cylinder and an annular piston cooperating with and within said cylinder to generate a gas stream, a blowing chamber surrounding said rod and forming an extension of said cylinder, said rod being straight and passed through said cylinder and said chamber, a sleeve open at both ends surrounding said rod in said cylinder with space left between said rod and the inner wall of said sleeve, spiders connecting said sleeve to said rod, said annular piston being mounted on said sleeve and said sleeve being adapted to guide the gas stream generated in said cylinder to said blowing chamber during the separation of the electrodes, a nozzle in said chamber opposite said insulating tube to discharge the gas stream, said rod being passed through said nozzle with little clearance in the closed circuit breaker position and being adapted to uncover the nozzle opening during the separation of the electrodes.

BERNARD MARIE HILAIRE PAUL FERNIER.

nEFERENoEs CITED The following references are 'of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 2,051,659 Ueberrnuth Aug. 18, 1936 2,267,399 Farrer et al Dec. 23, 1941 1,959,183 Uebermuth May 15, 1934 2,310,093 -orndorfer Feb. 2, 1943 2,039,838 Saudicoeur May 5, 1936 2,279,040 Grosse Apr. 7, 1942 2,032,149 Rawlins Feb. 25, 1936 FOREIGN PATENTS Number Country Date 507,634 Great Britain June 15, 1939 817,526 France May 24, 1937 839,522 France Apr. 5, 1939 830,526 France May 16, 1938 

